Perhaps you peered longingly at your Princess Beanie Baby behind its plastic case, admiring its purple form and ensuring its tag protector was tightly fastened. The bear benefitting The Diana, Princess of Wales Memorial Fund was a crown jewel in a Ty toy collector's assortment.

A look at eBay listings might enforce that notion. One bear described as in "near mint" condition is listed for $507,000. And it's not the only bear with a six-figure price tag.

But as antiques appraiser Lori Verderame, who has appeared on Discovery Channel's Auction Kings, advises, an item's worth should be based on what it's actually sold for. "When you see... $507,000, that’s not credible because you have to find a sales record for someone (who) actually paid the bill for that."

The sold for prices tell another story.

In July, a version of the bear — because yes, there are different versions — sold for $1,000. Another sold that same month for just $1.

So how much is your Princess really worth? As Dr. Lori explains a "magic number doesn’t exist" as many factors come into play, including the condition and version of the bear. Is the tag still attached or has it fallen off? Also, different versions of the Princess bear were made in different parts of the world with different materials. Dr. Lori says a bear filled with PVC pellets "is key to the high evaluation."

The upcoming 20-year anniversary of Princess Diana's death on Aug. 31 makes now an ideal time to sell, she advises.

"These two weeks before the end of August... is really the time when people should be focusing on ‘This is the time to sell my Diana Beanie Baby,’ because the market only spikes at certain times — usually at 25 years, 50 years, 100 years," she says.

To those perusing eBay for a Princess bear, Dr. Lori issues a warning about sellers. "They’re not gonna tell you what it’s really worth because they want you to buy it for the highest price possible."

Dr, Lori explains the hope that one's Beanie Baby collection could be valuable shouldn't be lost. "Anytime you have such big numbers of production, you’re gonna have some that are worth less than others," Dr. Lori reasons, "But because it’s a Beanie Baby, we all think automatically, ‘Oh it can’t be worth anything,’ and that’s really a mistake."

For future collections, focusing on items that have a historical context is a good rule of thumb, according to Dr. Lori. "Collect stuff that relates to history," she says, "because it will increase in value."